Iron, biochemistry

The similarity (89,152) between the chemical properties of AP+ and Fe explains why aluminum can be taken up and distributed in animals it uses the iron distribution pathway. However, aluminum is unlikely to replace iron in many, if any, of its functional sites. Thus, for example, AF+ has not been found in significant amounts in heme. The damaging effects of AP appear to arise because, once mobilized within the body, it can replace Mg + and Ca (83, 89), and also because insoluble aluminum-containing materials are formed. Thus aluminum toxicity is probably not directly related to iron biochemistry. 

Ferritins present several of the features of iron biochemistry mentioned above. They sequester iron in a safe form as a hydrous ferric oxide-phosphate mineral inside a protein coat. The protein, a hollow shell, has a capacity for up to about 4000 Fe atoms by virtue of its ability to pack this iron in its interior in a mineral form (11). The molecular design renders an otherwise insoluble mineral soluble and, by enabling iron to traverse the shell, allows a relatively high surface area of mineral to equilibrate with cytosolic iron. In eukaryotes, iron acquisition and release by ferritin may be to some extent compartmentalized. In higher organisms, iron may be deposited... 

In this article we propose to survey the role of iron as a conformational determinant in polypeptides and in non-haem proteins. This aspect of iron coordination research has been either ignored or only sporadically dealt with in reviews concerned with metalloproteins. By stressing this often circumstantial aspect of iron biochemistry it is our hope that the relevance of metals in general as fundamental structural factors in biomolecules will be brought into proper perspective. 

Gilles-Gonzalez MA, Gonzalez G, Perutz MR Kinase activity of oxygen sensor FixL depends on the spin state of its heme iron. Biochemistry 1995 34 232-236. 

PS Brereton, FJM Verhagen, ZH Zhou, MWW Adams. Effect of iron-sulfur cluster environment m modulating the thermodynamic properties and biological function of ferredoxm from Pyrococcus furiosus. Biochemistry 37 7351-7362, 1998. 

In addition to its role in preventing scurvy (see Human Biochemistry box Ascorbic Acid and Scurvy and also Chapter 6), ascorbic acid also plays important roles in the brain and nervous system. It also mobilizes iron in the body, prevents anemia, ameliorates allergic responses, and stimulates the immune system. 

R. Crichton, Inorganic Biochemistry of Iron Metabolism, Ellis Horwood, Kernel Hempstead, 1991, 212 pp. 

Halliwell, B. and Gutteridge, J.M.C. (1986). Oxygen free radicals and iron in relation to biology and medicine—some problems and concepts. Archives of Biochemistry and Biophysics 246, 501-514. 

Figure 6-6. The iron atom moves into the plane of the heme on oxygenation. Histidine F8 and its associated residues are pulled along with the iron atom. (Slightly modified and reproduced, with permission, from Stryer L Biochemistry, 4th ed. Freeman, 1995.)...

The biochemistry of the porphyrins and of the bile pigments is presented in this chapter. These topics are closely related, because heme is synthesized from porphyrins and iron, and the products of degradation of heme are the bile pigments and iron. 

Nackerdien, Z., Rao, G., Cacciuttolo, M.A., Gajewski, E. and Dizdaroglu, M. (1991). Chemical nature of DNA-protein cross-links produced in mammalian chromatin by hydrogen peroxide in the presence of iron or copper ions. Biochemistry 30, 4872-4879. 

Pereira MM, Carita JN, Teixeira M. 1999. Membrane-bound electron transfer chain of the ther-mohalophilic bacterium Rhodothermus marinus Characterization of the iron- sulfur centers from the dehydrogenases and investigation of the high-potential iron- sulfur protein function by in vitro reconstitution of the respiratory chain. Biochemistry 38 1276. 

D. E. Crowley and D. Gries, Modeling of iron availability in plant rhizosphere. Biochemistry of Metal Micronutrients in the Rhizosphere (J. A. Manthey, D. E. Crowley, and D. G. Luster eds.), Lewis Publishers, Boca Raton, Florida, 1994, p. 199. 

Oxygen activation is a central theme in biochemistry and is performed by a wide range of different iron and copper enzymes. In addition to our studies of the dinuclear non-heme iron enzymes MMO and RNR, we also studied oxygen activation in the mononuclear non-heme iron enzyme isopenicillin N synthase (IPNS). This enzyme uses O2 to transform its substrate ACV to the penicillin precursor isopenicillin N [53], a key step in the synthesis of the important P-lactam antibiotics penicillins and cephalosporins [54, 55],... 

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